Manage your subscription

Science: Ozone loss extends beyond Antarctic hole

9 December 1989

THE HOLE in the ozone layer above Antarctica returned in the spring
of 1989. But researchers in the US also found that ozone was significantly
depleted far beyond the boundaries of that hole (Nature, vol 342, p 233).

According to the scientists, from the US National Oceanic and Atmospheric
Administration’s Aeronomy Laboratory, and the University of Colorado (both
in Boulder), ‘the geographic extent of the ozone loss (is) larger than that
generally identified (and) ozone is lost earlier in the year than previously
reported’.

They base their conclusions on measurements made by the ER2 research
aircraft on a flight between California and Chile. The measurements show
that at all southern latitudes down to 50 degrees, as much as 15 per cent
of the stratospheric ozone was lost in August, and 30 per cent in September.
This is outside the region subject to polar temperatures.

Above Antarctica itself, chemical reactions that take place on the surfaces
of ice particles release chlorine in an active form. This attacks ozone.
Outside this polar region, however, there are few ice particles. One explanation
for ozone loss in these areas is that active chlorine is being released
by similar reactions taking place on the surfaces of sulphuric acid droplets.